Process of manufacturing inner tubes



,634,160 June 28, E927. C. H' SEMPLE ROCESS OF MANUFACTURING INNER-TUBES Filed Dec, 23. .1924 2 Sheets-Sheet 1 June 28 1927.

c. H. sEMPLE PROCESS OF MANUFACTURING INNER TUBES IK` l 2 Sheets-Sheet 2 Filed Dec. 23. 1924 IWW KDN

www@ sk @NNN Patented June. 2s, 1927.

UNITED 'STATES CHARLES HERBERT SEMPRE, OF YOUNGSTOWN, OHIO, ASSIGNOR, BY DIRECT AND PATENT OFFICE.

MESNE ASSIGNMENTS, TO SEMPLE-LEE PROCESSES, INC., OF AKRON, OHIO, A COR- PoRArIoN or DELAWARE.

PROCESS OF MANUFACTURING INN-ER TBES.

` Application led Decemberl23, 1,924. Serial No. 757,693.

This invention relates to 'the'art of making annular rubber tubes such as inner tubes for -tires and its chiefobject is to provide improved procedure whereby tube stock, and

especially stock extruded from a tubing ma vulcanization of a large number of tubes aty the same time in a vulcanizer of given size; and to provide a finished tube of desirable cross-sectional form and with desirable uniformity of wall thickness. This object I attain in the following manner, reference being had to the accompanying drawings, in which:

Fig. 1 is a diagrammatic view showing a 'tube being placed yin a mold as it comes from any ordinary tubing machine;

1 Fig. 2 is a sectional view on the line 2 2,

Fig. 1;

Fig. 3 is a sectional view of the tube mold, with a tube in position to have the ends joined and the valve reinforcement put in place; f

' c Fig. 4 is a diagrammatic view of the valve Fi 7 is a view showing one form of joint,

or spr'ce, of the. tube ends;

y Fig. 8 is a plan view showing the steps in the work of producing Atubes by vmy improved process;

Fig. 9 is a view, in elevation, of the appa-u'` ratus shown in Fig. 8;

Fig. l0 is a sectional view illustrating a series of tube molds mounted on a vulcanizer car, one above another, and secured together,

with the rubber tubes therein prior to being vulcanized; and

Fig. 11 is a view of a. finished tube. Referring 'to the drawings, 1 is the discharge nozzle of a tubing machine. 2 is a mold, so located as to receive the hot rubber tube a as it comes from the tubing machine,

as shown in Fig. 1. The mold is mounted,

preferably on a rotatable table 3, Fig.. 2.`

The unvulcanized rubber is placed in the tubingI machine in the ordinary manner and is projected from the tubing machine in the form of a tube, which is directed at once, and while hot, into a circular mold of the proper diameter. This may be the vulcanizing mold for `the inner tube, or a temporary form. In some instances, it may be a piece of'iiat materialwith a guide to indicate the vcorrect diameter.

The tube is cut oi the exact length from the tubular material coming from the tubing machine, and, the mold, or form, is placed on the carrier c, Fig. 8. Another mold, or form, is placed on 'the table 3, and the operation is repeated, A

The carrier c, Fig. 8, travels inharmony with the speed of the discharge` of rubber from the tubing machine so that, when one complete tube 'has been discharged from' the tubing machine, there is suiiicient s ace on the end of the carrier next 'to the tubing machine to receive the mold, or form, just filled. The object ofthis-is to cool, or temper, the stock so that it will be of the right temperature to be handled most advantageously ghensit reaches the warm splicing table d,

1g. Y The operator stationed on the carrier c places into the tube the'proper amount of water, ammonia, or other iniatant, before passing it to 'the operator at the warm splicing table d.

The ends may be joined by telescopind, but I refer to make the joint by cuttin o square yeach end of the circular tube, ig.

7, 'inserting a guide- A, which is preferably made of soft, bulky aper, or straw board, and which is prefers. ly tapered at one end. This guide serves the purajohse of preventing 'the unvulcanized rubber vering within the tube after it has been washed with high test naphtha, or benzol, and facilitates the entire operation.

After the ends of a tube have been washed and brought together over a guide, they adhere at once, making a perfect union. The outer surface around the joint is then washed and a. strip of unvulcanized rubber is wrapped around it. During the vulcanization, this strip of rubber andthe rubber of the inner tube are formed into a homogeneous piece of rubber so that there is no chance for air leakage.

From the splicing table, the tube is passed to table e, Fig. 8, where the valve reinforcement 4, Figs. 4 and 5, is put in place. The valve may be attached to this reinforcement, in which case-if desired-the iniiation of the inner tube against the walls of the mold may be made with air, instead of water, ammonia, or other inflatant.

A hole of correct size to receive the valvestem of the inner tube is punched in the fabric of the valve reinforcement 4 and in this hole, when the tube is to be vulcanized while distended by a sealed-in infiatant, is placed a metal disk, or plug, 5, Fig. 5, which iseasily broken out when vulcanization is completed thereby making it possible to. insert the va ve.

Molds for this work should be light so that they can be handled easily, therefore,'aluminum meets 'this requirement. The mold, Fig. 2, is made with an inner annular rib, which extends upwardly to engage and register with the mold above it. The under side of one mold forms the top of the mold below it,-

with the exception of the irst and last molds, which'are made one-sided for economy of space.

The molds may be placed in Ithe vulcanizer in an desired number, from one to the capacity llmit of the vulcanizer.

he molds are placed, preferably, one on top of another on a car 6, after which they are lirmly bolted, or clamped, together. The car is run into the vulcanizer 7 and live steam i's turned on to efect the'vulcanization. y In some cases, a vertical vulcanizer maybe used instead of the horizontal vulcanizer described and the molds may be clamped together by hydraulic pressure.

When `the tubes are taken from the vulcanizer and the valves are attached, they are ready to be packed and delivered to the shipping room.

It is unnecessary to iniate, test and deflate the tubes, as a leak in a tube will prevent it from expanding during vulcani- /zation and the defect is evident as soon as a mold'is o ened.

The mol preferably are of such form as to deline mold cavities of oblate cross-sectional form as shown, with a less maximum dimension in an axial than in a radial dimanico rection, so that a large number of tubes may be assembled in a stack of molds of iven length or height, and so that the iinished tube may have an outside diameter greater than the outer diameter ofthe tire cavity which it is to occupy and an inner diameter less than the inner diameter of the said tire cavity, and thus be adapted to be readily inserted in the tire, t-o fit snugly and without slack material at the beads of the tire and to have rubber in its tread portion put under compression, for puncture proof purposes, as an incident of its chan e of shape upon iniiation. Such a tube is escribed 1n my copending application Ser. No. 85,735, filed February 3, 1926. Notwithstanding the great difference between the outer and inner peripheral lengths of such a tube, I find that it can be formed by the above-described method without undesirable wrinkling or thickening of its inner peripheral walls or excessive thinning of its tread portion.

The method hereinbefore described for joining the ends of the tube forms the subject of a separate application for patent, Ser. No. 757,691, led even 'date herewith. The mold hereinbefore described also forms the sub'ect of a separate application for patent, er. No. 757,692, tiled even date herewith.

I claim :y

1. The method of making collapsible end-l less rubber tubes which comprises shaping hot rubber stock into a continuous `tube of closed cross-sectional form,.bending the tube in such cross-sectional form to appjroximately its final condition of longitudinal curvature before substantial cooling of the tube, the tube being bent by uniform pro'- gression of external bending forces along the tube without full-section internal support of the tube in the region of such forces, cutting successive lengths from the curved portion of the continuous tube, joining together the two end's of respective lengths, and vulcanizingl the resulting endless tubes under internal fluid pressure.

2. A method as defined in claim 1 in which the length of the tube before its ends are joined is given a cross-sectional form such that it is appreciably more extensive in a radial than in an axial direction and in which the endless tube is vulcanized in that form in a mold.

3. The method of. making collapsible endless rubber tubes which comprises shapin rubber stock into a continuous tube of close cross-sectional form, bending the tube in such cross-sectional form to approximately its -nal condition of longitudinal curvature, the tube being bent by uniform procutting successive lengths from the curved joined is given a cross-sectional form such portion of the continuous tube, joining tothat it is appreciably more extensive in a gether the two ends of each length, and vulradial than in anaxial direction and in 1 canizing the resulting endless tubes under which the endless tube is vulcanized in that 5 internal fluid pressure. form in a, mold.

4. A method as defined in clziim 3 in which the length of the tubebefore its ends/ are CHARLES HERBERT SEMPLE. 

